title: Visible light-induced decomposition of a fluorotelomer unsaturated carboxylic acid in water with a combination of tungsten trioxide and persulfate.
abstract: Photochemical decomposition of a fluorotelomer unsaturated carboxylic acid, C3F7CFCHCOOH (1), in the presence of WO3 and an electron acceptor (S2O8(2-) or H2O2) in water under visible-light irradiation was investigated. Under an O2 atmosphere, 1 was not decomposed either by TiO2 (P25) or WO3 alone. A combination of WO3 and H2O2 also resulted in almost no decomposition of 1. In contrast, irradiation in the presence of a combination of WO3 and S2O8(2-) (potassium salt) efficiently decomposed 1 to F(-), CO2, C3F7COOH, and C2F5COOH. The decomposition of 1 was affected by the counter cation of S2O8(2-): the decomposition extent was higher with K2S2O8 than with (NH4)2S2O8. The decomposition of 1 was further enhanced when the reaction in the presence of WO3 and K2S2O8 was carried out under an argon atmosphere. Under O2, the amount of H2O2 formed in the reaction solution was an order of magnitude higher than the amount formed under argon. This fact suggests that the decrease in the decomposition of 1 under O2 can be ascribed to the formation of H2O2, which consumed S2O8(2-) and SO4(-).
authors.affiliation: Department of Chemistry, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka 259-1293, Japan; National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba West, 16-1 Onogawa, Tsukuba 305-8569, Japan. Electronic address: h-hori@kanagawa-u.ac.jp.
authors.forename: Hisao
authors.initials: H
authors.lastname: Hori
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ishiguro
authors.forename: Kohei
authors.initials: K
authors.lastname: Nakajima
authors.forename: Taizo
authors.initials: T
authors.lastname: Sano
authors.forename: Shuzo
authors.initials: S
authors.lastname: Kutsuna
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Koike
mesh_terms: D002264:Carboxylic Acids / Q000737:chemistry; D005466:Fluorocarbons / Q000032:analysis / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D008027:Light; D008956:Models, Chemical; D010087:Oxides / Q000737:chemistry*; D055668:Photochemical Processes; D013431:Sulfates / Q000737:chemistry; D014414:Tungsten / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D002264:Carboxylic Acids; D005466:Fluorocarbons; D010087:Oxides; D013431:Sulfates; D014874:Water Pollutants, Chemical; C511604:tungsten oxide; D006861:Hydrogen Peroxide; D014414:Tungsten
keywords: Degradation; Fluorine; Peroxodisulfate; Photocatalyst; Surfactant